Generally there exists a variety of different stacked assemblies and structures in the context of e.g. electronics and electronic products such as various electronic devices.
The motivation behind stacking elements in a common structure may be as diverse as the related use contexts. Relatively often size savings, weight savings, cost savings, usability benefits, or just efficient integration of components in terms of e.g. the manufacturing process or logistics is sought for when the resulting optimized solution ultimately exhibits a multilayer nature. In turn, the associated use scenarios may relate to product packages or food casings, visual design of device housings, wearable electronics, personal electronic devices, displays, detectors or sensors, vehicle interiors, antennae, labels, vehicle and particularly automotive electronics, etc.
Electronics such as electronic components, ICs (integrated circuit) and conductors may be generally provided onto a substrate element by a plurality of different techniques. For example, ready-made electronics such as various surface mount devices (SMD) may be mounted on a substrate surface that ultimately forms an inner or outer interface layer of a multilayer structure. Additionally, technologies falling under the term “printed electronics” may be applied to actually produce electronics directly and additively to the associated substrate. The term “printed” refers in this context to various printing techniques capable of producing electronics/electrical elements from the printed matter, including but not limited to screen printing, flexography, and inkjet printing, through a substantially additive printing process. The used substrates may be flexible and printed materials organic, which is however, not necessarily always the case.
A substrate such as a plastic substrate film, may be subjected to processing, e.g. (thermo)forming or molding. Indeed, using e.g. injection molding a plastic layer may be provided on the film, potentially then embedding a number of elements such as electronic components present on the film. The plastic layer may have different mechanical, optical, electrical, electrical, etc. properties. The obtained multilayer, or stacked, structure may be configured for a variety of purposes depending on the included features, such as electronics, and the intended use scenario and related use environment. It may, for instance, comprise one or more connecting features such as fluke type protrusions for coupling with compatible recesses of a host element or vice versa.
As the electronics may not, however, always be a critical or sole feature of highest priority or of most importance in the associated product, and they may actually be considered supplementary, optional features only, the design and implementation of features providing the desired electrical effect shall be carefully executed. Weight and size requirements, elevated power consumption, additional design considerations, new process steps, and generally increased overall complexity of the manufacturing phase and the resulting product are all examples of numerous drawbacks easily becoming materialized as a side effect of adopting various electronic features in the target solution.
In the light of the foregoing, in many real-life manufacturing scenarios fitting all the desired electronic or generally electrical features on a substrate film has turned out very challenging if not impossible due to the limited surface area available for mounting or producing the features thereon and e.g. the necessary physical separation some elements should in any case have to function in optimal or even proper manner. Further, in some applications placing several features on a common substrate either adjacent to each other or at a distance is sub-optimum in any case as the resulting rather limited spatial separation of the features reduces the achievable spatial resolution of the implemented functionality, which may be a sensing functionality, for instance.